Nimbus RAT - Teams Vishing to Quick Assist Reconnaissance
This rule detects a multi-stage attack chain associated with the Nimbus RAT, starting with a suspicious Microsoft Teams message (vishing) from an external sender using throwaway domains (e.g., .onmicrosoft.com, .top). This initial communication is then correlated with subsequent reconnaissance activities performed via Quick Assist, where QuickAssist.exe spawns cmd.exe to execute commands like 'net time', '/domain', 'whoami', 'ipconfig', or 'systeminfo' on the victim's device within a two-hour window. The rule aims to identify the internal victim and the external sender involved in this coordinated attack.
Microsoft Sentinel (KQL)
